Convection-compensating centrifuge



Feb. 5, 1952 c. F. HALL CONVECTION-COMPENSATING CENTRIFUGE 2SHEETS-SHEET 1 I Filed July 22, 1946 5, 1952 c. F. HALLCONVECTION-COMPENSATING CENTRIFUGE 2 SHEETS-SHEET 2 Filed July 22, 1946eg I I I I I Patented Feb. 5, i952 "25-84345 V E i 7CONVECIIONi-COMBENSATING CENTRIFUGE v 'CharlesF. Hall, Ber ra -camApplication July 22, 1946,".Serial' 685,393 scams. (circa-f1):Myinvention relates to-a continuous flow, cross current,"Convection-Compensating Centrifuge, in which separation offiuidconstituents of different-mass is accomplished by means of adjacentoppositely flowing component axial currents having component crosscurrents which flow predominantly centrifugal across one axial currentand predominantlycentripetal across the opposite axialcurrent; thusproviding a-high resolving power free of remixing defects. It showsalternative and supplementary methods and improvements relating tocopending patent applications Serial No. 583,33l filedflvlarch 17',1-945, now abandoned; Serial No. 624,761, filed Octoleer 26, 1945 nowabandoned; Serial No. 654,753, filed March 15, 1 946,.now abandoned; andPatent No. 2,546,186, issued March 27, .1951. main feature is arotor'comprising heat insulative and heat conductive partition segmentsin combination 'with a central cooling system, to provide necessarytemperature gradients within the rotor.

Throughout the specification and claims the term axia or axially is usedto denote a directionparallel or componentl-y parallel to'the axis ofthe centrifuge rotor; thusthe expression axially inclined perforations"designates perforations that are inclined to provide a component offluid flow in adirection that is parallel to theaxis; and the term axialseparation designates a separation or enrichment of separableconstituentsthat takes place in a direction that is parallel .to theaxis. The term centripetaPlis used to denote a direction radially inwardtoward the axis of the rotor. Theterm centrifugal is' used todenote adirection radially outward from the axis of the rotor. And the termcircumferentia1-is used to denote a direction extending through the cordof .an arc concentric to the circumference of the rotor. The wordradially is used in its broadest sense to denote radii extending ascomponents of centrifugal force. The term centripetal cross current isused to denote a radially inward component of current that crosses acomponent of axial current. The term fcentrifugal crosscurrent is usedto denote a radially outward component of current that crosses acomponent-axial current. The term axial current isused to denotecomponent axial current.

In the accompanying drawings: Fig. l "is a horizontallongitudinalsection of the device, se'ctioned onthe .line I+I,. Eig..'3and Fig. 4. vFig.

2 isa reflected view of asection on theline 2'12',:

Fig.4. Fig. 3 is a reflected View of=a segment seetionedon the line 3-3, Fig. Fig; 4 is a reflected view'of a. segment sectionedon the line4-4, Fig.1. Fig. 5}is n-end view andfl igfld is an elevation of ene ofthe heat insulative haill segments. Fig.- 7 is .a reflected end riew 1or one flue-assectioned-ontheline 4--4f, Fig. 1'; it-shqws arrows toindicate the flow of fluid around a baffle segment; especiallyshowingcentrifugal. and centripetal cross currents. Fig. e is .a sectionthrough-a fine on ;the line 88, FigQ'Z, and a section through a 'bafliesegment on the liii T8;

Fig. 5; it shows arrows to in dicate the newer fluid around a .bafliesegment. especially showing axial currents; Fig. 9 is a sec'tion on theli n 9- -.9, Fig 25;- it is a view of .a broken :;partlo'f amid-:leng-th of a baffie segment showing ascends of axially inclined,pertorations. Simi1ar numerals refer-to similarpartsthroughoutthedrawings. The tubular stationary axle l is divfidd iiltdthreeinternal channels by th e threesidd partition 2. I-t is attached tothe beam .3, to the stationary disk 4 to thesmooth suriacdlsleve gaskets& and 6, and to the radial extension 9 H Thelong cylindrical outer wall8, of therefor, is attached to the end disk and .fiiehihrf attachedtorthe drive gear n and qarrymg ni bearings .l,l.- I t -is alsoattached-to thiend dish and huh-member l2 carrying thebearingsfi' andattached tothe innereylindrical wall llheriiiet'i cally sealed to theinner disk oaps 5 and [6 attached to the inner lhub members {1 iandll't.The annular channels 9 and ill are I filled with oil or mercurywhich..provides centrifhgallliduid seals around each annularfiang'e ofeach of the two sleeve gaskets 5 and fi. Theannular space, between thecylindrical walls 8 i and 14, ispartitioned into axial 'flues 49 by theheatinsiilatiize" baffle segments-2|, by the heat conductivelsefiments-22 conductive to the wall 8 and ib'y ft he heat conductive segments 13conductive to the wallld. t I I :Each flue 48 iscireurn'ferentiallydivided radially and axially extending ba'fil s'egriifit Zl. Near the-radially outer part of each-balii'fi ment are the axially inclinedperforations 9 and near theradially inner'ipart of each name.sefg'imerit airethe axially inclined perforations The perforations fand 30 have the same iaxi '7 inclination for anyfigiv'en tame segment a.fiue, but .for the parallel connection or muss" shown, the axialinclination dfLthe perforations is reversed in every alternate flue,.so'fthatithey have the same inclination fifacingLtowardsidppositesidesof their common heat idonduetivfsg mentzlhsee-Fig. '9.

For a device oflarger vection currents between the parallel connected.

The tubular stationary axle 3| is divided into two internal channels bythe partition 32. It is attached to the beam 33 and toithe stationarycentral cooling system 34 carrying the bearings 35 supported on therotary inner hub H. A cold liquid is circulated through the internalchannels of" the axle 3| and through the longitudinal coils 35 of thecentral cooling system. By means of convection and radiation the centerof the rotor is thus cooled, and since the heat conductive segments 23make better thermal contact, with the center wall i i of the rotor, theyare more quickly and effectively cooled than are the segments 2| and 22,and so a circumferential temperature gradient is established across eachflue between each segment 22 and 23. This circumferential temperaturegradient across each flue is augmentedby convectional displacement ofcool fluid from the radially inner wall and warm fluid-from the radiallyouter wall of each flue.

Supported on the beams and enclosing the rotor is the stationary,electrically heated housing 31 which is divided into the end lengthcompartments covered with the electric heating units 38 and 39, and themid-length compartment covered with the electric heating unit 40. Therings 4| and 42 serve to restrict convectional transfer of heat betweencompartments of the housing 31. So that heat from the-unit 40 goesdirectly to the mid-length of the rotor, and heat from the units 38 and39 goes directly to the respective end-lengths of the rotor. Themid-length heating unit 40 is electrically connected through thediagrammatically shown electrical connections 49 and in operation it maybe maintained at a higher temperature than the end-length heating units38 and 39 Z which are electrically connected through thediagrammatically shown electrical connections 54 and 55, respectively.Axial temperature gradients, produced by heat conducted from thebearings, are thus roughly neutralized throughout the rotor.

Fluid,having molecular, colloidal or other constituents to be separated,is fed through the Y connection tube 44 into the channels 5| connectingto an extension tube 1 which connects to the inlet chamber 43. 'As shownin Fig. 3, this extension tube 7 is curved in the direction of rotationso that rotation of the fluid in the chamber 43 sucks fluid through thetube. The diametrically opposite extension tube 1, Fig. 1', is curved inthe opposite direction to rotation so that the rotating fluid iscompressed into its end and is forced throughthe channel 52. Thechannels 5i and 52 are connected together, through an inlet chamber of asecond centrifuge not shown, and thus fluid is continuously circulatingandmixing, through these channels.

From the inlet chamber 43 the fluid and its constituents passes throughthe diffusion plugs 28 and int'othe flues 48.

Considering the flow of fluid in one flue 48."

as shown by the arrows in Figs. 1, '7, and 8: the heat conductivesegment 22 is heated by its contact to the periphery of the rotor andthereby warms fluid on one side of the baffle segment 2|; and the heatconductive segment 23 is cooled by its contact to the center of therotor and thereby cools fluid on the opposite side of the baffiesegment. This circumferentially unbalances the centrifugal head ofpressure so that fluid passes from the cooled side of the flue to theheated side through the axially inclined perforations 29 along theradially outer part of the baffle segment and-it passes from the heatedside to the cooled side through the axially inclined perforations 30along the radially inner part of the baflie segment. In passing throughthe axially inclined perforations it is given an axial circulation; thusas seen in Fig. 8, there is a downward cooled axial current on thecooled side and an upward heated axial current on the heated side; andas seen in Fig. '7, there is a centrifugal cross current on the sameside as the downward cooled axial current and a centripetal crosscurrent on the same side as the upward heated axial current. Within thefluid are both heavy and light weight separable constituents which areaffected by centrifugal force and for the illustration given herein itis considered that the heavier constituents have faster centrifugalsedimentation velocities than the lighter constituents. For separationof constituents such as molecules or colloidal particles the velocity ofthe cross currents is greater than the, centrifugal sedimentationvelocities of the constituents; and so the cross currents carry theconstituents around the baffle segment. Due to the diflerences' incentrifugal sedimentation velocities, the lighter constituents, ascarried in the centrifugal cross current, travels slower than theheavier constituents and thus the lighter constituents are enrichedwithin the cooled axial current and are displaced and axially enrichedin the direction of said cooled axial current. But in the centripetalcross current the heavier constituents travel slower than the lighterconstituents and thus the heavier'constituents are enriched within theheated axial current and are displaced and axially enriched in thedirection of said heated axial current. The axial enrichment isdependent upon averaged differences in the summation of the centrifugaland centripetal cross currents and sedimentation velocities ascircumferentially maintained by the bafile segment. It is not dependentupon maintaining a state of centrifugal enrichment and so it is notadversely affected by centrifugal and centripetal circulation of thefluid which destroys or defects the centrifugal enrichment necessary inother types of centrifuges.

For a full length rotor the mid-length of a flue may be three or fourfeet long so the total aggregate open area of the perforations extendingalong a baffle segment is large to provide a large volume of crosscurrent circulation. To shorten end affects and complete circulationthere are diagonally opposite openings 46 and 41' at the ends of eachbaffle segment.

For the example given herein the cooled axial current is directed towardthe inlet chamber 43 and so the enrichment of lighter constituents,

'' toward the annular outlet chamber 25 and so the enrichment of heavierconstituents, from each flue 48, diifuses through the diflusion plugs 28into the chamber 25. In one of the fiues, shown at the right of Fig. 1,the bafile segment 2| and difiusion plugs 28 are omitted and a cap 24closes one end of the flue. This flue is in open communication at oneend with the annular outlet chamber 25 and at the other end communicatesthrough hole 2'! with outlet 26 in open communication with the channel53, Fig. 2, which connects to the outlet duct 45 through which theenrichment of heavier constituents may be drawn 01f.

Instead of being extended axially, the fiues may be extendedcircumferentially or in any desired direction which is componentlytransverse to the direction of the centrifugal field.

I claim:

1. In a centrifuge a cylindrical rotor, a central cooling system axiallyextending through the center of the rotor, end-length and mid-lengthheating units peripherially surrounding the rotor, said rotor having aplurality of fiues axially extending therethrough for the circulation offluid carrying separable constituents, a bafiie segmentcircumferentially dividing each flue, each bafile segment having amultiplicity of closely spaced axially inclined perforations passingthrough a radially outer part of the baflle segment and a correspondingmultiplicity of closely spaced axially inclined perforations passingthrough a radially inner part of the baflie segment, in each flue and onone side of the baffle segment within the flue a heat conductive segmentin thermal contact with the radially outer heated wall of the rotor andthermally insulated from the radially inner cooled wall of the rotor andon the opposite side of the baflle segment within the flue a heatconductive segment in thermal contact with the radially inner cooledwall of the rotor and thermally insulated from the radially outer heatedwall of the rotor, said heat conductive segments providingcircumferential temperature gradients across each flue thereby producingconvectional circulation of fluid through the axially inclinedperforations and said perforations being so positioned that thecirculation produces oppositely directed component axial currents oncircumferentially opposite sides of each bafile segment and producescomponent cross currents which flow predominantly centrifugal across onecomponent axial current and flow predominantly centripetal across theoppositely directed component axial current, at opposite ends of therotor annular inlet and outlet chambers connecting the ends of the fluesto inlet and outlet ducts, connected to the ducts within the chambersstationary extension tubes to circulate the fluid through the ducts andthereby discharge an enrichment of constituents as enriched by thecirculation of fluid within the fiues.

2. In a centrifuge a cylindrical rotor, a central cooling system axiallyextending through the center of the rotor providing radial temperaturegradients throughout the rotor, axially extending through the rotor anumber of fiues circumferentially divided by perforated bafile segmentsthrough which fluid and separable constituents circulate,circumferentially on one side of each flue a heat conductive segment inthermal contact with the radially outer heated wall of the rotor andthermally insulated from the radially inner cooled wall of the rotor andon the cir cumferentially opposite side of the flue a heat conductivesegment in thermal contact with the radially inner cooled wall of therotor and thermally insulated from the radially outer heated wall of therotor, said heat conductive segments providing circumferentialtemperature gradients across each flue the said perforations being sopositioned that the temperature gradients produce convectionalcirculation of fluid and enrichment of constituents within the fiues.

CHARLES F. HALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 723,152 Gurber Mar. 17, 19031,061,656 Black May 13, 1913 1,126,247 Mason Jan. 26, 1915 1,527,076Peck Feb. 17, 1925 2,003,308 Podbielniak June 4, 1935 2,176,982 ThayerOct. 24, 1939 2,286,157 Podbielniak June 9, 1942 2,291,849 TomlinsonAug. 4, 1942 2,394,367 Beese Feb. 5, 1946 2,422,882 Bramley June 24,1947 OTHER REFERENCES Smyth: Atomic Energy for Military Purposes,published August 1945, by U. S. Government Printing Oifice, Washington,D. 0., pages 117, 118 and 123.

